[sdiy] Ferrite Beads

[Barry Klein]

Years ago I put ferrite beads (cores, not smt) on input resistors and VCC 
pins of guitar amp op amps and saw a huge
reduction in rf rectification/interference when testing with a CB radio 
right nearby.  That's probably
their best use in a synth - in high gain circuits with non-fet input op 
amps.
Also, probably some debate, but likely not a good idea to put the ferrites 
in the ground path.  Keep
in the VCC path and input circuits.

Barry

----- Original Message ----- 
From: "Matthew Smith" <matt at smiffytech.com>
To: "Stewart Pye" <stewpye at optusnet.com.au>
Cc: "Synth DIY" <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, February 02, 2011 13:50
Subject: Re: [sdiy] Ferrite Beads


> Quoth Stewart Pye at 03/02/11 07:45...
>> It's common (good practice) practice to put ferrite beads on the power 
>> supply inputs to a module. Would it also be good practice to put them on 
>> audio inputs to a system that uses banana sockets (unshielded cables), or 
>> does RC filtering at your input op amp do just as good or better job?
>
> Speaking of ferrite beads, I've been wondering about boards with both 
> analogue and digital sections. The grounds of both need to be connected 
> (at the DAC) - should this be a link with a bead on it rather than just 
> being part of the same ground plane?
>
>
> -- 
> Matthew Smith
>
> Blog: www.smiffysplace.com  Business: www.smiffytech.com
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